Unstick oil control rings on 1zz?

[m1tch]

Hi all,

Just wanted to ask if there was a solution to unstick the oil control rings on the 1zz, I am aware that the earlier models had only 4 oil holes in the piston which then sludge up and cause the oil control rings to stick and cause oil usage and oval bore. I know that the later models were fixed using the revised pistons but was just wondering if anyone had any solutions in terms of unsticking the oil control rings for the earlier engines without taking the pistons and rods out etc. Are there any products on the market that could loosen up the oil rings and holes or is it a case that all of the older engines will have issues with the bores etc?

I can't remember what year of MR2 the engines were fixed (think it was '03 or '04?) - still researching into the best base project car to use for a turbo conversion etc.

[lamcote]

I expect Carolyn will be along soon with all the advice you will ever need.

[krazysteve]

If there is a remedy to solve that with out stripping the engine, patent it.  s:lol: :lol: s:lol:  
Sorry it's a strip down job.
Plenty of snake oils out there that claim they do miracles on engines.

[Carolyn]

Hi,

Steve is correct.  It's engine out and strip it down.

The myths;
'Later engines don't have the problem'.  Only in the very last months was the piston modified.  I've rebuilt an 05 because of oil control rings.
'The bores go oval.'   No they don't.  They usually just need a light hone and new rings.  Buggered bores are a result of massive amounts of oil in the exhaust causing the precats to break up.

I've rebuilt quite a few of these now.  Never found a bad bore.  Never found a bad crank.  Have found bad valve stem seals (especially exhaust as they get hot and go brittle).  Have found stuck rings every time.

Oil control rings do not show up as blue smoke, bad valve seals do show blue smoke.

We modify the pistons on the mill, while we've got them out.  We enlarge the holes, with a slight overlap on the bottom groove, and add an extra two.

One of our members is being coached through a rebuild in our workshop right now.  You might find the thread useful...

 l viewtopic.php?f=6&t=62276 l

[lamcote]

Told you!

[Carolyn]

Told you!

You did.  You did indeed.

[m1tch]

Hi,

Steve is correct.  It's engine out and strip it down.

The myths;
'Later engines don't have the problem'.  Only in the very last months was the piston modified.  I've rebuilt an 05 because of oil control rings.
'The bores go oval.'   No they don't.  They usually just need a light hone and new rings.  Buggered bores are a result of massive amounts of oil in the exhaust causing the precats to break up.

I've rebuilt quite a few of these now.  Never found a bad bore.  Never found a bad crank.  Have found bad valve stem seals (especially exhaust as they get hot and go brittle).  Have found stuck rings every time.

Oil control rings do not show up as blue smoke, bad valve seals do show blue smoke.

We modify the pistons on the mill, while we've got them out.  We enlarge the holes, with a slight overlap on the bottom groove, and add an extra two.

One of our members is being coached through a rebuild in our workshop right now.  You might find the thread useful...

 m http://mr2roc.org/phpBB3/viewtopic.php?f=6&t=62276 m

Thanks for this info, I figured that there wasn't really a product out there that could unstick a design flaw in the pistons, good to know that the bores don't have the issue although I have seen a few videos of pistons slapping from side to side - guess this would be due to the precat material breaking up due to the design flaw with the oiling and the owner not removing the precat material.

I only ask as I am looking at the options to either turbo the 1zz or drop in a 2zz, both have their flaws, the 1zz being the thinner weaker rods and piston issues and the 2zz having lift bolt issues as well as the fact that the bores are MMC meaning not all pistons are compatible and they can't be rebored plus liners are expensive.

Will look at the options for the engine I would want to swap in when the stock 1zz has issues, either a built up 1zz with uprated rods and pistons with a turbo or a 2zz with some aftermarket Mahle pistons that are ok with MMC bores. Tempted to lean towards a built 1zz engine ready for a turbo as the bores can be rebored and honed plus everything will bolt up including the stock gearbox with the stock LSD.

[1979scotte]

1zz pistons and rods are silly money 2zz is much cheaper.
Not that i would bother.
You can run 300bhp on stock 2zz with a rotrex supercharger.
Thats plenty in a light weight car.

[m1tch]

1zz pistons and rods are silly money 2zz is much cheaper.
Not that i would bother.
You can run 300bhp on stock 2zz with a rotrex supercharger.
Thats plenty in a light weight car.

You do make a good point, might as well go with an engine that makes more power as stock from the same displacement rather than putting money to tune the lower powered engine to the stock power levels of the 2zz, guess why its such a popular swap.

[1979scotte]

Only issue for me is lack of torque from 2zz but that is actually an advantage with the c series gearbox because it cant cope long term with more than 250lbft.
If you like torque then i reccomend a V6.

[m1tch]

Only issue for me is lack of torque from 2zz but that is actually an advantage with the c series gearbox because it cant cope long term with more than 250lbft.
If you like torque then i reccomend a V6.

I guess there is also the matter of the lift part way through the rev range, its why I was still looking at the 1zz as that would have a linear power delivery vs top end boost in performance with the 2zz - although just means that when running the engine flat out you will always be in the lift zone and then be out of the lift zone when going from A to B.

[1979scotte]

Linear power = supercharger

[m1tch]

Linear power = supercharger

Indeed, although I am sure that the 2zz would still have the same characteristic when it hits lift SC or no SC.

[1979scotte]

Linear power = supercharger

Indeed, although I am sure that the 2zz would still have the same characteristic when it hits lift SC or no SC.

If you lower the rpm at which lift engages then it is less distinct.
Thats what i have been told.

[KRAMSNEHPETS]

Correct, my lift is now at 5500 with the supercharger on the 2zz. No real change when lift comes in as the charger is giving me some lovely torque!
Headcase is due to fir me a new engine soon with a rotrex so my existing will be available for sale

[m1tch]

Correct, my lift is now at 5500 with the supercharger on the 2zz. No real change when lift comes in as the charger is giving me some lovely torque!
Headcase is due to fir me a new engine soon with a rotrex so my existing will be available for sale

Good to know, I guess with forced induction the air is being pushed into the cylinders rather than with it NA it suddenly has a restriction removed as the valves open more on lift. It will be quite a while before I get to adding any forced induction - still need to source the project car first! I can see that in your sig its running 225bhp which sounds like a good figure to aim for as its only a bump higher than the stock 2zz vs where the 1zz would need to get from to run the same power.

I think the plan might be to run with the stock 1zz engine, boost that a bit whilst upgrading the ECU, suspension etc and then having a 2zz ready to swap in when the time comes when the 1zz needs a rebuild. Hopefully in the time it takes between owning the car with the 1zz and mildly boosting it I can get a 2zz and drop in some rods and Mahle pistons (so I can run with the stock MMC coated sleeves) and swap it in.